When the ascent module of the Lunar Excursion Vehicle (LEV) lifted off the surface of the Moon during the
Apollo program, it made rendezvous and docked with the Command Service Module (CSM) in one orbit. This
timing was considered so crucial that NASA worked on perfecting the technique during Gemini. The Space
Shuttle typically takes three days to rendevous with the International Space Station (ISS) or another
target. I have heard this is due to crew and ground support schedules. But if a rescue was necessary,
could a Shuttle launch and rendezvous with the ISS within one orbit (90 minutes), assuming a Shuttle was
ready to launch?- question from Scott

The answer, essentially, is no. The standard Shuttle rendezvous takes about 1.5 to 2 days to get to a burn point
called "Ti" (Terminal Initiation) in its orbit. Once the Ti burn takes place, the Shuttle goes through another
set of pre-planned burns that allow it to successfully rendezvous with the ISS. From Ti to dock is approximately 3
hours.

Now in theory, the Shuttle could launch directly to the Ti burn point. The main reasons they don't do that is to
allow the crew time to adjust to space (i.e. getting over initial space sickness for first-timers) and also time
to re-configure the Shuttle's systems from ascent mode to orbit mode. The crew also needs time to prepare all of
the necessary rendezvous systems, sensors, etc. All of this (as well as about 1,000 other things I don't even
know about) takes the crew about 1-2 days to complete.

Now like I said before, in theory the Shuttle could launch directly into Ti. However, to successfully pull that
off would require about a year's worth of prep time beforehand to perform all of the necessary analysis,
generate/test/validate all the necessary procedures, etc. But even if you had all of that, to launch perfectly to
the Ti point would give you about a about a 3-second launch window maybe once every 8 days or so. And even if you
got the launch off perfectly, and could reconfigure all of the systems and prep for rendezvous in record time, to
fly the rendezvous profile that would allow you to successfully dock with the ISS still takes about 2 more orbits
after that.
- answer by Aaron Brown, 13 October 2002